Index: app/models/message_observer.rb
===================================================================
--- app/models/message_observer.rb	(revision 1354)
+++ app/models/message_observer.rb	(working copy)
@@ -21,6 +21,8 @@
     recipients = ([message.root] + message.root.children).collect {|m| m.author.mail if m.author && m.author.active?}
     # send notification to the board watchers
     recipients += message.board.watcher_recipients
+    # send notification to all users in the project who want to know all
+    recipients += message.board.project.users.select {|u| u.mail_notification}.map {|u| u.mail}
     recipients = recipients.compact.uniq
     Mailer.deliver_message_posted(message, recipients) if !recipients.empty? && Setting.notified_events.include?('message_posted')
   end